Electric installation in combination with pressure-splitting device



" May 27, 1 930 A. D. RICCIA ELECTRIC INSTALLATION IN COMBINATION'WITHPRESSURE SPLITTING DEVICE Original Filed Dec. 2, 1921 2 Sheets-Sheet 112 :3 fly] 7417 {6/0 DELL/4- F/ c 0 M? A. D. RlcclA 1,760,777

ELECTRIC INSTALLATION INCOMBINATION WITH PRESSURE SPLITTING DEVICE 2Sheets-Sheet 2 Original Filed Dec. 2, 1921 such as motors for traction,hoisting, etc,

Patented May 2?, i939 ANGJELQ DELLA BICQIA, @F BRUfiSELS, BELGIUMELEGTRIG INSTALLATION IN CGMBINhTIQN WITH PRESSURE-SPLITTING DEVICEoriginal application filed. December 2, will, Serial No. 519,553, and.in France December it, 192%. Divided and this application filed August12, 1927.. Serial No.212,5?0.

T he invention relates to the use of a direct current pressure splittingdevice or transformer for the'supplying of electric current of variablepressure to electric apparatus motors for rolling mills, storagebatteries, etc., from a main power line at a substantially constantpressure. In the case of applying the device to the regulating of thesupply of motors for traction, hoisting, or the like, the losses ofenergy in starting resistances or in mechanical brakes on de'scents andon stops, are avoided, and a regeneration of energy takes place ondescent,

aid pressure splitting device provides for the division of the main linepressure V into difi'erent parts, all of which are at will con--tinually variable; the'use of gradually increasing or decreasingpressures upon the electric apparatus, produces a reduction of lossesduring the operation or" said apparatus, while at the same time, the useof connections allowing the electric energy to proceed as much aspossible directly from the main line to said apparatus, and thus toreduce as far as possible, the use of the transformer elements (armatureor their parts) allows a.

reduction in site and weight of and in said elements. The pressuresplitting device may on the other hand fulfill various secondaryfunctions of a useful nature, such as driving at suit-able speed ofexciters or other auniliary apparatus which may he necessary to carrythe invention properly into 'efi'ect,

According to the invention, the pressure splitting device which isprovided is the device described in the application tier. No. 519,558,filed Dec. 2, 1921, whereof the present case is a divisionalapplication. Said pressure splitting device thus comprises as vdescribedin said application Ser, No. 519,558, tour armatures-or armature partsmounted on the same shaft and connected in series between the twoterminals of the main distributing line, the two end armature windingsbeing equal and arranged in a symmetrical manner withrespect to the twoterminals or the line and the two intermediate armature windingsheingalso equal and arranged in asymmetrical manner with respect to the same,and respective fields for all said windings, with means, known per se,to vary at will equally the fluxes through the two end armature windingsand to also vary at will equally, but in another manner as in the endwindings, the fluxes through the two intermediate armature windings.

F or applying said device to the regulating or the supply of electricalapparatus, these apparatus are subdivided into two equal separate groupsthe outer terminals. of which are permanently connected to the outerterminals of the transformer while their inner terminals are connectedto variahle points between the armatures or armature parts of thetransformer according to the phase of the operation. When applied to theregulating oi the supply of traction or hoisting motors, the motors ofeach of the two separate groups sometimes are connected in shunt withone of the respective armatures or armature parts, and sometimes inshunt with the whole of the said end armatures or armature parts and theentire intermediate portion, the motors then acting either as motors oras generators.

The sum of the partial fluxes in the four armaturcs or armature partsmay be, if desired, approximately constant; in this case, the pressuresplitting device, as a whole, may constitute a motor adapted to drive,at a substantially constant speed, an auxiliary apparatus such as anindependent exciter serving to excite the motors, when these areconstructed as series motors, thus converting the same into separateexcited motors with or without compound series winding, so as to providefor regeneration during descent or braking.

The middle armatures or armrture parts in some cases are preferablyjoined to form a single armature or armature part.

lln the drawings forming a part hereof Fig. 1 is a diagram of a knownarrangement comprising a transformer with three armatures supplying aworking apparatusor group of apparatus.

ig. 2 is a diagram of the arrangement according to my invention,comprising a pressure splitting device with three symmetrical lydisposed armatures traversed by fluxes varying symmetrically, andsupplyin groups of working apparatus whose distribution 1s 11.50symmetrical.

Fig. 3 shows the general arrangement of a pressure splitting device withfour armature parts or sections, the connections being modified at willby symmetrical switches K K I Fig. 4 shows the general arrangement of aplant comprising an independent exciter mounted on the shaft of thedevice and serving to excite the working motors.

Fig. 5 shows the application to the charging or discharging of a storagebattery.

Fig. 6 shows another form of the general arrangement with an ex'citerenergized by compound windings.

Figs. 7 and 8 show other forms with an excite! energized by independentwindings.

The device comprises four armatures or armature parts A A A A mounted ona common shaft and placed in series, in the indicated order, between theterminals of the main line, at the substantially constant pressure V;these four armatures or armature parts bein subjected to the action oftwo fields or o a field divided into two or three parts producing twoequal magnetic fluxes (or a single flux through A and A and two otherfluxes through A and A so that A shall produce at each instant the samepressure as A and that if A is separate from A" the part A will producethe same pressure as A It is however remembered that as explained in thepatent application above mentioned the two intermediate parts A 2 A maybe combined in a single armature part A The working apparatus, such asmotors or battery, which are to be regulated, are divided into two equalgroups M and M the end terminals of which are permanently connectedwith-the terminals of the main line while their intermediate terminalsare variably connected with two terminals situated between A and A andbetween A" and A direct connections are used whereby the apparatus M,can be subjected to the pressure of A and the apparatus M to thepressure of A crossed connections are used whereby the apparatus M aresubjected to the combined pressure of A A: and Af' and the apparatus Mto the combined pressure of A A 2 and A The two groups M M are thus inall cases subjected to two equal pressures, but these are taken from twoseparate and symmetrical parts of the transformer. This distinction andthis symmetrical disposition constitute together with the permanency ofthe connection between the end terminals of the two groups M M and theterminals of the main line, the factors causing the exceptional economyof my present system of regulation,

as compared to all other systems of like nature.

When the fluxes respectively passing through the elements A and A andthe elements 'A and A" 2 are so regulated that the sum of all the fluxesis substantially constant, the device, as a whole, may be employed as amotor at a substantially constant speed, for driving an auxiliaryapparatus, more particularly an exciter for the motors. In particular, asuch arrangement may be used for transforming series-motors intoseparately excited motors with compound arrangement represented by apart of the series winding, or without any such compound winding, ifthis excitation is replaced as a whole. With this disposition, one mayemploy motors designed for traction, hoisting, or like purposes whichare normally series-excited motors as generators which will offer arecuperation of energy on down-grades and upon braking.

In order to assist in the explanation of the invention, reference willnow be made to Figures 1 and 2 of the accompanying drawin s whichillustrate simple diagrams for use in explaining the principle on whichthe invention is based.

It is recognized that if it is desired to supply working motors M at avoltage varying etween O and V, a converter of the motorgen'erator typemay be used having two armatures, motor and generator, in series at thevoltage V, the generator armature supplying a voltage e varyin from O toV, and the motor armature wor ring at a voltage e varying from V to O; e+e ==V.

Another method would be to use a transformer (Fig. 1) consisting of twoend armatures 1 and 3 and an intermediate armature 2 interposed between1 and 3, the voltage e being subdivided between the two end armatures.In such a case, however, the current could not be su plied to theoperation motor M without pass ng through the two end armatures 1 and 3of the transformer.

The invention relates to an improved arrangement of a transformingdevice of this character, which is of-a more economical na ture, as itenables a part of the energy of the main distribution circuit to passdirectly to the motors (Fig.2), and it also enables the recovery ofenergy by the said motors during descent or reduction of speed bybraking, said motors possessing or being provided for this purpose withan excitation enabling their operation as generators in a reliablemanner.

In order to enable a part of the energy to pass directly from the maindistribution line into the working motors M according to the invention,the said motors are constructed with two separate windings and twocommutators each, or are subdivided into two separate groups M M as Fig.2 (each group consisting of a single motor of a'number of inotors) and Iprovide a pressure splitting device, of which the armature is dividedinto four armatures or armature parts A A A" A (of which A A may bejoined together to form a single armature or armature part A means arealso provided for connecting each group of motors M M firstly, in shuntrespectively with the armatures or armature parts A or A secondly inshunt respectively with the whole of the armatures or armature parts A Aand the intermediate armature or armature part A -viz. A i-A or A +A insuch a manner that a part of the current pass directly from the mainlineto the two groups of motors M and M or vice-versa without traversing theparts A and A of the device. For this reason, the system is advantageousin that it is highly economical.

In order to effect a regeneration of energy, the motors, if excited inseries, are converted into separately excited motors, with or without acompound series winding, by meansof an independent exciter which shouldoperate as far as possible at constant speed. According to theinvention, the pressure splitting device may be so arranged that the sumof the variable partial fluxes in the different arma tures or parts ofthe armatures A A A will be practically constant, and consequently thewhole arrangement, when employed at practically constant voltage of themain line, may constitute in itself a motor at practically constantspeed for the independent exciter.

Referring now to Fig. 3 (where the motors are represented as compoundwound motors), and to Fig. 4 (where the motors are repre sented asseries wound motors with their field windings cut into two portions, asit will be explained further), the central armature A of the machine (orthe middle part A of the armature) is assumed to be divided into twoparts A3 A for the sake of clearness.

' On a common shaft are mounted four armatures or armature parts A A A Aconnected together in series (with all the E. M. F.s addedarithmetically), these armatures or armature parts being supplied withthe distribution line voltage V which is assumed to be constant.

In the following description (which applies more particularly to Fig. 4)it is assumed that the two groups of motors M M are of a similar nature,then it must be e =e this being obtained by regulation so that fh x 5 Itwill also be assumed that With such an arrangement, -the operation willbe as follows. Let 71 represent the current in each group of motors M orM 6 5 the current in the armatures A and. A and 3 i =z' the current inthe armaures A" and A g. I

(a) First period of starting. The motors M and M are switched into thecircuit by placing switches K and K uponcontacts 1 and 1, the double twoway the two E. M. F.

switches S and S closing-the four openings ab and switch F is open. Themotors M and M including field portions 11"11" and 13"13, are thusconnected in shunt with the end armatures A and A respectively, frompoints 10 to 11 and from points 13 to 14.

In order to provide a first minimum startin value of the fluxes therheostats 1', r bymeans of which said fluxes 4 (which are equal inrespect of each other) are regulated, are first placed on the firstcontact, while 1* and 1" contrarily are placed so as to provide themaximum value of 41' and 4W The equal fluxes 4 qb subsequently areincreased, or the equal fluxes and are decreased to supply to the motorsM and M e and e 'which are always equal and greater than their propercounter E. M. F. Parts A and A of the pressure splitting device act asgeneratorsand parts A' and A" as motors, the power circuit supplying tothe motors M and M and the transforming device a current which(neglecting the currents t representing transformer losses) is equal tothe diiference between 5 and i, and power which increases from zero toVi, each motor or group of motors M and M absorbing power whichincreases from zero to l 2 At the end of this period, the

two groups of motors may be connected in series with each other byplacing switch contacts K and K on contacts 2 and 2 which lead to themiddle point 12 of the transforming device.

(5) Second period of starting.

The switches K and K are placed upon contacts 3 and 3, so that the motorgroup M is connected between points 10 and 13, and the group M betweenpoints 11 and 14;. The equal fluxes and as, are decreased; or the equalfluxes b' and S" are increased, so that the motor groups will still besupplied with equal E. His e -l-e 0" and e +e +e which are alwaysgreater than their proper counter E. M. F.s. Parts A and A of thepressure s litting device now act as motors and parts A and A" asge'nerators, the power circuit supplying power which increases from Vito 2 Vi and each of the motor groups M and M absorbing power Vi 5 130Vt. of this operation, which completes the starting period,'the motorgroups M and M may be connected in parallel by placing switches whichincreases from K and K on contacts 4 and 4, each being series woundmotors, with their field wind ings cut in two parts 10-11' and l111 forthe motors ofi group M and 14='-13' and 13"13f for the motors of group Mare suitably excited by the auxiliary exciter E mounted on the shaft ofthe pressure splitting device, to enable them to operate reliably asgenerators and would thus be capable (in addition to the braking efi'ectwhich they might produce in parallel in accordance with theircharacteristics at constant volt age V) of producing a braking eflectaccord ing to the two following periods.

(a) First braking period.

The switches K and K are placed on contacts 3 and 3 switches S and S thedouble two wa closing the four opening 0d, and switch M and M, are thuswith their permanently connected field portions 10--11 and1413,@connected between points 10 and 13 and points 11 and 14,respectively, while the field portions 1111' and 13"-13"' are connectedin series with each other and with the exciter E. The equal fluxes 4 and4 are increased, or the equal fluxes 4J and S are decreased, so as tosupply to the motors of groups M and M now acting as genera- ,tors, twocounter E. M. F.s e -l7e' +e and e +e" +e which are always equal andsomewhat below their proper E. M. F.

During the starting periods and normal workin the field winding portions10'11 and 11 -11"', and likewise parts 1413 and 13"13', were acted uponby the same magnetizing current (the current taken by the motor). Duringthe braking periods, on the contrary, the field winding portions I1011'and 1413 are acted'upon by a demagnetizing current (the currentsuppliedby the motors acting as generators) while the portions 11"11" and13-13"', are acted upon by the magnetizing current supplied by exciter Ewhich is driven by the transforming device.

The action, as a whole, is similar to that which takes place during thesecond period of starting, except that the fluxes change in the oppositedirection, that part of the field windings of the motors M and M aredifferentiallyexcited, and that 2' is greater by reason of the addedlosses in the auxiliary exciter E. At the end of the period the switchesK and & may be moved to contacts Zand 2.

-. (03) Second braking period.

Switches K and K are placed on contacts 1 and 1; the other switchesbeing left in the positions shown in the drawings, that is, thepositions described for the first braking period. The motor groups M andMg are thus connected between points 10 and 11 and points 13 and 14,respectively; and the equal fluxes 4 and 4);, are decreased, or theequal fluxes and are increased so as to supply to the groups of motors Mand M which are now acting as generators, two counter E. M. F.s. c and cwhich are always e ual and somewhat less than their proper F.

is closed. The motors of groups The action, as a whole, is similar tothat which takes place during the first period of starting except forthe diiierences which have been indicated above.

At the end of this period the regulating rheostats 1' 1' consequent-1yare returned on their first contact corresponding to the minimumpositive valve of the fluxes (minimum starting value of said fluxes).

During the starting, the current i is regulated by controlling, by meansof the transforming device, the excess of voltage supplied to the motorsof groups M and M in relation to the counter E. M. F. which they produceat the instant speed. During the braking, the regulation is carried outin a similar manner by adjusting the lack of voltage supplied to themotors in relation to their E. M. F. The motors may be started andbraked at constant current, or with variable current, as may be desired.

Each of four windings A A A 2 A will alternately absorb and supply amaximum power V2 and an average power V2; the group of four windingsthus corresponds to a temporary maximum power Vi which is equal toone-fourth the power of the motors which are supplied with current, theaverage power of the group during the intermediate periods to A, Viwhich equals one-sixth of the power of the motors supplied with current.

Moreover, all the machines have a voltage V instead of voltage V, whichis an important advantage for small machines.

The left of Figs. 3 and 4 shows four slides and four resistances inseries with the four fields. In the same figure a and a are twoammeters.

The four positions of the switches 71: 70 correspond to the followingconnections: position (1.) to the periods (a) and (d) when each group ofmotors is in shunt with one end portion and in series withtheintermediate and the other end portion of the pressure splitting device;position (2) to the operation of the two groups of motors in serieswithout including any portion of the pressure splitting device in seriestherewith; position (3) to the periods (6) and (a) when each group ofmotors is in shunt with one end and the intermediate portions and inseries with the other end portion of the pressure splitting device;position (4) to the operation of the two groups of motors in parallelwithout including any portion of the pressure splitting device in seriestherewith.

I will here better explain the functioning of the series wound motorswith auxiliary field windings. As shown in Fig. 4, the armatures of thetwo groups of motors M M, are directly connected to the points 10 and 14of the regulating machine or group. Subsequent to these armatures aredisposed the field windings 10, 11' and 14 13 whose. ends 14" and 13"should be connected with magnetizing current during the starting and thenormal working (the current taken by the motors), and by a demagnetizingcurrent during the braking and the operation or regeneration (thecurrent supplied by the motors). The parts 11', 11" and 13 13 areconnected duringthe starting and in normal operation with the parts 1011' and 14' 13' and receive the same magnetizing current as the latter;During the braking and the recuperation on the contrary, they aredisconnected from the preceding and connected with a small exciter Edriven by the machine or by the group and supplying a specialmagnetizing current to the fields of the motors M M Said exciter may beenergized either by a shunt field or by an independent field. TheFigures 7 and 8 show two independent excitations, the field winding n nbeing connected (Fig. 7) across points 10 and 14: that is under apressureV, or (Fig. 8) across the points 10 and 12 that is under apressure 5 It is understood of course that the same ressure can beattained by connecting the neld across the points 12 and It In the caseof series wound motors with field windings cut in two parts, eightgeneral conductors are used, two whereof proceed to the two groups ofmotor armatures and six are brought respectively from all the points 11'11 11" 13' 13" 13", in order to carry out all the required controloperations. As regards apparatus, the following are required: twodouble. two way switches S and S one of which for respectivelyconnecting the four-pointswitches K K either with the conductors broughtfrom the terminals 11' and 13" during the period (a) and (b) or with theconductors brought from the terminals 11 and 13" during the periods (0)and (d) ;'and one of the same for respectively connecting the twoconductors brought from the terminals 11" and 13", either with theconductors brought from the terminals 11' and 13 during the periods (a)and (b), or with the positive and negative terminals of the auxiliaryexciter E during the periods (c) and (d); and a simple switch F forconnecting the conductor brought from the terminals 11" with theconductor brought from the terminals 13 during the periods (0) and (d)and for braking this connection during the periods (a) and (b). Thesefive apparatus may on the other hand be combined in a single device withtwo positions, one for the starting and,the other for the braking.

It is easily understood that instead of using compound wound motors itis possible to use a compound wound exciter E, the compound windings ofthis exciter being fed by the current of the motors in such manner thatwhen starting and during normal operation, said exciter is acted upon bya magnetizing current, i. e. by the current taken by the m0- tors, whileduring braking and regeneration it is acted upon bya demagnetizingcurrent, i. e. by the current supplied by the motors.

Fig. 6 shows such a device in which the exciter E is provided with ashunt winding.

n n (or an independent excitation winding fed at pressure V or 2 7 and8) and with compound windings m and m fed by the current of the motors Mand M The pressure splitting devices according to the invention may alsobe used for the complete charging and discharging of a storage batteryinserted in a line working at constant tension. Fig. 5 shows a diagramof connections for this purpose.

The battery is divided into two equal parts 6 b" which are mountedbetween the line and the points 11, 13, of the armature of the machine.In the case of a line at 210 volts and a battery of 100 cells, thebattery may be charged, using the cross connections shown in dash anddotted; lines, by supplying to each half of the battery 700 amperes at135 as shown in Figs.

volts, which would require 900 amperes from the line, the middle part ofthe armature A AJ' acting as negative booster for the batter and on theother hand, the battery may e discharged, using the direct connectionsshown in dotted lines, by taking from each half of the battery 1050amperes at 90 volts and supplying 900 amperes to the line, the middleparts A A" acting as booster for the battery.

What I claim is:

1. In combination with a main distributinf line of substantiallyconstant pressure, a irect current pressure splitting device with twoextreme and at least two intermediate symmetrical terminals, with meanssymdiate parts of the device, finally in shunt between the two terminalsof the line.

2. In combination with a main distributinf line of substantiallyconstant pressure, a irect current pressure splitting device with twoextreme and at least two lntermediate symmetrical terminals, with meansto maintain substantially constant the speed of-said pressure splittingdevice disposed so as to symmetrically vary the pressures at theintermediate terminals with respect to the pressures applied to theextreme terminals of the device, and two balanced groups of electricapparatus to be controlled, the apparatus 0 each group being connectedin parallel and each group being connected permanently to one of the twoterminals of the main line and means to connect each of said balancedgrou s first in shunt with the end part of the evice connected to thesame terminal of the main line, then in shunt with this end and theintermediate parts of the device, and finally in shunt between the twoterminals of the line.

3. In combination with a main distributingl line of substantiallyconstant ressure,- a 'rectcurrent pressure splitting evice with twoextreme and at least two intermediate symmetrical terminals, with meanssymmetrically disposed to vary the pressures at the intermediateterminals with respect to the pressures applied to the extreme terminalsof said pressure splitting device, two balanced grou s of electricseries motors to be controlled, t e motors of each group being connectedin parallel and each group being connected permanently to one of the twoterminals of the main line, means to connect each of these groups firstin shunt with the end part of the device connected to the same terminalsof the main line, then in shunt with this end and the intermediate partsof the device and finally in shunt between the two terminals of theline, an exciter mounted on the shaft of the pressure splitting de vice,and means for inde endently connecting said exciter to the field; of thetwo groups of motors whereby said motors may operate as generators forregenerative braking.

4. In combination with a main distributingi line of substantiallyconstant ressure,

rect current pressure splitting evice. with two extreme andat least twomtermediate symmetrical terminals, with means to maintain substantiallyconstant the speed of said pressure splitting device disposed so as tosymmetrically vary the prewures at the intermediate' terminals withrespect to the res-- sures applied to the extreme termina s of thedevice, two balanced groups of electric series motors to be controlled,the motors of each group being connected in parallel and each oup beingconnected permanentl to one o the two terminals of the main ine, meansto connect each of these groups first shunt between the two terminals ofthe line,

an exciter mounted on the shaft of the pressure splitting device, andmeans for independently connecting said exciter to the fields of the twogroups of motors whereby said motors may operate as generators forregenerative braking.

5. In combination with a main distributingl line, of substantiallyconstant ressure,- a 'rect current pressure splitting evice with twoextreme and at least two lntermediate symmetrical terminals, with meanssymmetrically disposed to vary the pressures at the intermediateterminals with respect to the pressures applied to the extreme terminalsof said pressure splitting device,two balanced grou s of series woundmotors to be controlled, t e motors of each group being connected inparallel and each group being connected permanently to one of the twoterminals of the main line, means to connect each of said motor groupsfirst in shunt with the end part of the pressure splittin deviceconnected to the same terminal of t e main line, then. in shunt withthis end and the intermediate parts of the device, and finally in shuntbetween the two terminals of the. line, an exciter mounted on the shaftof the pressure splitting device, field windings for each motor wound intwo unequal arts and means to inde endently connect t e larger of saidfield windings of each grou to the exciter and to maintain the smal erfield windings in series with the respective motor armatures wherebysaid motors ma operate as generators for regenerative bra 'ng.

6. In combination with a main distributincp line of substantiallyconstant ressure, a irect current pressure splitting evice with twoextreme and at least two intermediate symmetrical terminals, with meansto maintain substantially constant the speed of said pressure splittingdevice disposed so as to symmetrically vary the pressures at theintermediate terminals w th respect to the pressures applied to theextreme terminals of the device, two balanced oups of series woundmotors to be contro ed, the motors of each group being connected inparallel. and each group being connected permanently to one of the twoterminals of the main line, means to connect each of said motor groupsfirst in shunt with the end part of the pressure splittin deviceconnected to the same terminal of t e main line, then in shunt with thisend and the intermediate parts'of the device, and finall in shuntbetween the two terminals of the ine, an exciter mounted on the shaft ofthe pressure splitting device, field windings for each motor wound intwo unequal parts and means to independently ANGELO DELLA RICCIA.

